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  • Import? Initialize? what do to?

    - by Jeremy B
    I'm working on homework and I'm close but I am having an issue. I just learned how to work with packages in eclipse so I have a class that is importing another class from a package (I think I said that right) The main prompts the user to enter an integer between -100 and 100 and I am having an issue with validating it. I know the issue is where I'm importing I'm just unsure the direction I need to go to fix it. This is a section of my main code. (my issue starts with the last couple lines if you want to skip ahead) import myUtils.util.Console; public class ConsoleTestApp { public static void main(String args[]) { // create the Console object Console c = new Console(); // display a welcome message c.println("Welcome to the Console Tester application"); c.println(); // int c.println("Int Test"); int i = c.getIntWithinRange("Enter an integer between -100 and 100: ", -101, 101); c.println(); I have a class called Console that is located in another package that I believe I have properly imported. here is the code I am stuck on in my console class. public int getIntWithinRange(String prompt, int min, int max) { int i = 0; boolean isValid = false; while (isValid == false) { System.out.println(prompt); if (sc.hasNextInt()) { //if user chooses menu option less than 1 the program will print an error message i = sc.nextInt(); if (i < min) { System.out.println("Error! Please enter an int greater than -100"); } else if (i > max) { System.out.println("Error! Please enter an int less than 100"); } else isValid = true; } else System.out.println("Error! Invalid number value"); sc.nextLine(); } // return the int return i; } when I run this I keep getting my last print which is an invalid number value. am I not importing the code from the main method in the other console properly?

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  • Getting all objects with a certain element inside a collection of strings with criteria API.

    - by Jens Jansson
    Hey. I'm trying to build a Hibernate Criteria query to find entities that have a specific element inside a collection. We can take as an example a Book -object that looks like this: public class Book { private Long id; private String title; private Set<String> authors = new HashSet<String>(); } The entity is mapped like this: <class name="Book" table="Book"> <id name="id" column="BOOK_ID"> <generator class="native"/> </id> <property name="title"/> <set name="authors" table="Book_Authors"> <key column="BOOK_ID"/> <element type="string" column="AUTHORS"/> </set> </class> Now I would like to find out which books are written by Matt. With pure SQL I can do a query like this: String author = "Matt"; String query = "SELECT * FROM Book " + "WHERE BOOK_ID IN " + "(SELECT BOOK_ID FROM Book_Authors " + "WHERE authors = :author )"; List<Book> result = session.createSQLQuery(query) .addEntity(Book.class) .setParameter("author", author) .list(); This works all good and well, and I get out all books that Matt has been a part of writing. The project I work in, however, uses the Criteria API instead of raw SQL, and I haven't found a way to express the same query in that form. I've taken a look on the Restrictions API and the closest I've found is Restions.in(propertyName, collection) but that works the other way around (one value in object, many values to match against). Any ideas?

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  • What would be the light way to render a JSP page without an App/Web Server

    - by kolrie
    First, some background: I will have to work on code for a JSP that will demand a lot of code fixing and testing. This JSP will receive a structure of given objects, and render it according to a couple of rules. What I would like to do, is to write a "Test Server" that would read some mock data out of a fixtures file, and mock those objects into a factory that would be used by the JSP in question. The target App Server is WebSphere and I would like to code, change, code in order to test appropriate HTML rendering. I have done something similar on the past, but the JSP part was just calling a method on a rendering object, so I created an Ad Hoc HTTP server that would read the fixture files, parse it and render HTML. All I had to do was run it inside RAD, change the HTML code and hit F5. So question pretty much goes down to: Is there any stand alone library or lightweight server (I thought of Jetty) that would take a JSP, and given the correct contexts (Request, Response, Session, etc.) render the proper HTML?

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  • Reducer getting fewer records than expected

    - by sathishs
    We have a scenario of generating unique key for every single row in a file. we have a timestamp column but the are multiple rows available for a same timestamp in few scenarios. We decided unique values to be timestamp appended with their respective count as mentioned in the below program. Mapper will just emit the timestamp as key and the entire row as its value, and in reducer the key is generated. Problem is Map outputs about 236 rows, of which only 230 records are fed as an input for reducer which outputs the same 230 records. public class UniqueKeyGenerator extends Configured implements Tool { private static final String SEPERATOR = "\t"; private static final int TIME_INDEX = 10; private static final String COUNT_FORMAT_DIGITS = "%010d"; public static class Map extends Mapper<LongWritable, Text, Text, Text> { @Override protected void map(LongWritable key, Text row, Context context) throws IOException, InterruptedException { String input = row.toString(); String[] vals = input.split(SEPERATOR); if (vals != null && vals.length >= TIME_INDEX) { context.write(new Text(vals[TIME_INDEX - 1]), row); } } } public static class Reduce extends Reducer<Text, Text, NullWritable, Text> { @Override protected void reduce(Text eventTimeKey, Iterable<Text> timeGroupedRows, Context context) throws IOException, InterruptedException { int cnt = 1; final String eventTime = eventTimeKey.toString(); for (Text val : timeGroupedRows) { final String res = SEPERATOR.concat(getDate( Long.valueOf(eventTime)).concat( String.format(COUNT_FORMAT_DIGITS, cnt))); val.append(res.getBytes(), 0, res.length()); cnt++; context.write(NullWritable.get(), val); } } } public static String getDate(long time) { SimpleDateFormat utcSdf = new SimpleDateFormat("yyyyMMddhhmmss"); utcSdf.setTimeZone(TimeZone.getTimeZone("America/Los_Angeles")); return utcSdf.format(new Date(time)); } public int run(String[] args) throws Exception { conf(args); return 0; } public static void main(String[] args) throws Exception { conf(args); } private static void conf(String[] args) throws IOException, InterruptedException, ClassNotFoundException { Configuration conf = new Configuration(); Job job = new Job(conf, "uniquekeygen"); job.setJarByClass(UniqueKeyGenerator.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(Text.class); job.setMapperClass(Map.class); job.setReducerClass(Reduce.class); job.setInputFormatClass(TextInputFormat.class); job.setOutputFormatClass(TextOutputFormat.class); // job.setNumReduceTasks(400); FileInputFormat.addInputPath(job, new Path(args[0])); FileOutputFormat.setOutputPath(job, new Path(args[1])); job.waitForCompletion(true); } } It is consistent for higher no of lines and the difference is as huge as 208969 records for an input of 20855982 lines. what might be the reason for reduced inputs to reducer?

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  • How do I recover from an unchecked exception?

    - by erickson
    Unchecked exceptions are alright if you want to handle every failure the same way, for example by logging it and skipping to the next request, displaying a message to the user and handling the next event, etc. If this is my use case, all I have to do is catch some general exception type at a high level in my system, and handle everything the same way. But I want to recover from specific problems, and I'm not sure the best way to approach it with unchecked exceptions. Here is a concrete example. Suppose I have a web application, built using Struts2 and Hibernate. If an exception bubbles up to my "action", I log it, and display a pretty apology to the user. But one of the functions of my web application is creating new user accounts, that require a unique user name. If a user picks a name that already exists, Hibernate throws an org.hibernate.exception.ConstraintViolationException (an unchecked exception) down in the guts of my system. I'd really like to recover from this particular problem by asking the user to choose another user name, rather than giving them the same "we logged your problem but for now you're hosed" message. Here are a few points to consider: There a lot of people creating accounts simultaneously. I don't want to lock the whole user table between a "SELECT" to see if the name exists and an "INSERT" if it doesn't. In the case of relational databases, there might be some tricks to work around this, but what I'm really interested in is the general case where pre-checking for an exception won't work because of a fundamental race condition. Same thing could apply to looking for a file on the file system, etc. Given my CTO's propensity for drive-by management induced by reading technology columns in "Inc.", I need a layer of indirection around the persistence mechanism so that I can throw out Hibernate and use Kodo, or whatever, without changing anything except the lowest layer of persistence code. As a matter of fact, there are several such layers of abstraction in my system. How can I prevent them from leaking in spite of unchecked exceptions? One of the declaimed weaknesses of checked exceptions is having to "handle" them in every call on the stack—either by declaring that a calling method throws them, or by catching them and handling them. Handling them often means wrapping them in another checked exception of a type appropriate to the level of abstraction. So, for example, in checked-exception land, a file-system–based implementation of my UserRegistry might catch IOException, while a database implementation would catch SQLException, but both would throw a UserNotFoundException that hides the underlying implementation. How do I take advantage of unchecked exceptions, sparing myself of the burden of this wrapping at each layer, without leaking implementation details?

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  • In a bidirectional JPA OneToMany/ManyToOne association, what is meant by "the inverse side of the as

    - by Bytecode Ninja
    In these examples on TopLink JPA Annotation Reference: Example 1-59 @OneToMany - Customer Class With Generics @Entity public class Customer implements Serializable { ... @OneToMany(cascade=ALL, mappedBy="customer") public Set<Order> getOrders() { return orders; } ... } Example 1-60 @ManyToOne - Order Class With Generics @Entity public class Order implements Serializable { ... @ManyToOne @JoinColumn(name="CUST_ID", nullable=false) public Customer getCustomer() { return customer; } ... } It seams to me that the Customer entity is the owner of the association. However, in the explanation for the mappedBy attribute in the same document, it is written that: if the relationship is bidirectional, then set the mappedBy element on the inverse (non-owning) side of the association to the name of the field or property that owns the relationship as Example 1-60 shows. However, if I am not wrong, looks like in the example the mappedBy is actually specified on the owning side of the association, rather than the non-owning side. So my question is basically: In a bidirectional (one-to-many/many-to-one) association, which of the entities is the owner? How can we designate the One side as the owner? How can we designate the Many side as the owner? What is meant by "the inverse side of the association"? How can we designate the One side as the inverse? How can we designate the Many side as the inverse? Thanks in advance.

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  • Timer Service in ejb 3.1 - schedule calling timeout problem

    - by Greg
    Hi Guys, I have created simple example with @Singleton, @Schedule and @Timeout annotations to try if they would solve my problem. The scenario is this: EJB calls 'check' function every 5 secconds, and if certain conditions are met it will create single action timer that would invoke some long running process in asynchronous fashion. (it's sort of queue implementation type of thing). It then continues to check, but as long as long running process is there it won't start another one. Below is the code I came up with, but this solution does not work, because it looks like asynchronous call I'm making is in fact blocking my @Schedule method. @Singleton @Startup public class GenerationQueue { private Logger logger = Logger.getLogger(GenerationQueue.class.getName()); private List<String> queue = new ArrayList<String>(); private boolean available = true; @Resource TimerService timerService; @Schedule(persistent=true, minute="*", second="*/5", hour="*") public void checkQueueState() { logger.log(Level.INFO,"Queue state check: "+available+" size: "+queue.size()+", "+new Date()); if (available) { timerService.createSingleActionTimer(new Date(), new TimerConfig(null, false)); } } @Timeout private void generateReport(Timer timer) { logger.info("!!--timeout invoked here "+new Date()); available = false; try { Thread.sleep(1000*60*2); // something that lasts for a bit } catch (Exception e) {} available = true; logger.info("New report generation complete"); } What am I missing here or should I try different aproach? Any ideas most welcome :) Testing with Glassfish 3.0.1 latest build - forgot to mention

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  • Tomcat: recommandations for logging

    - by WizardOfOdds
    I've read several questions here concerning Tomcat and logging but I still really don't understand the "bigger picture", hence my question: How and where are my Webapps supposed to do their logging? By default on my setup Tomcat 6.0.20 logs go in the following file/appender: ./apache-tomcat-6.0.20/logs/catalina.out Am I suppose to have my webapps also log to this file/appender? Let say my case is trivially simple and I've got just one servlet: import ... // What do I import here in order to be able to log? public class SOServlet extends HttpServlet { public void doGet( final HttpServletRequest request, final HttpServletResponse response ) throws IOException, ServletException { ... // I want to log here, what do I write? What are the gotchas knowing that there are more than one webapp running on the same Tomcat? (apparently from reading the various questions there are many gotchas). What about the .war, do I need to put log4j/sl4f/commons-logging/whatever in my .war?

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  • javascript server issue

    - by sarah
    Onchage of selection i am calling a javascript to make a server call using struts1.2 but its not making a call.Please let me know where i am going wrong,below is the code <html:form action="/populate"> <html:select property="tName" onchange="test()">"> <html:option value="">SELECT</html:option> <html:options name="tList" /> </html:select> </html:form> and stuts-config has <action path="/populate" name="tForm" type="com.testAction" validate="false" parameter="method" scope="request" > <forward name="success" path="/failure.jsp" /> </action> and javascript is function test(){ var selObj = document.getElementById("tName"); var selIndex = selObj.selectedIndex; if (selIndex != 0) { document.form[0].selIndex.action="/populate.do?method=execute&testing="+selIndex; document.form[0].submit(); } }

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  • How to make safe frequent DataSource switches for AbstractRoutingDataSource?

    - by serg555
    I implemented Dynamic DataSource Routing for Spring+Hibernate according to this article. I have several databases with same structure and I need to select which db will run each specific query. Everything works fine on localhost, but I am worrying about how this will hold up in real web site environment. They are using some static context holder to determine which datasource to use: public class CustomerContextHolder { private static final ThreadLocal<CustomerType> contextHolder = new ThreadLocal<CustomerType>(); public static void setCustomerType(CustomerType customerType) { Assert.notNull(customerType, "customerType cannot be null"); contextHolder.set(customerType); } public static CustomerType getCustomerType() { return (CustomerType) contextHolder.get(); } public static void clearCustomerType() { contextHolder.remove(); } } It is wrapped inside some ThreadLocal container, but what exactly does that mean? What will happen when two web requests call this piece of code in parallel: CustomerContextHolder.setCustomerType(CustomerType.GOLD); //<another user will switch customer type here to CustomerType.SILVER in another request> List<Item> goldItems = catalog.getItems(); Is every web request wrapped into its own thread in Spring MVC? Will CustomerContextHolder.setCustomerType() changes be visible to other web users? My controllers have synchronizeOnSession=true. How to make sure that nobody else will switch datasource until I run required query for current user? Thanks.

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  • Clean up upon the kill signal

    - by Begui
    How do you handle clean up when the program receives a kill signal? For instance, there is an application I connect to that wants any third party app (my app) to send a finish command. What is the best say to send that finish command when my app has been destroyed with a kill -9?

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  • select and jstl query

    - by sarah
    Hi All, I am displaying data in combo box using ${role} the requirement is on clcik of edit i want to show the preselected value in the drop down ,suppose i have cat,rat and i selected rat and i saved it in database ,now when i want to edit the details i want to show rat first in drop down as pre selected and then cat,how to od this ?

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  • How to get everything in the string, but a particular pattern

    - by José Leal
    Yet another regexp question: I have a string as the following, "This is a string, and I have a priority !1" So I want to build a regexp that extracts my priority, which is this number 1 preceded by the "!". To extract it is very easy, "!([1-4])". But now I want to extract the text, leaving it out! How can I do that? DETAIL: The !1 can be anywhere in the string, so this is also perfectly fine: "This is a string, !1 and I have a priority" Thanks! UPDATE: I'm using scala

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  • I am confused -- Will this code always work?

    - by Shekhar
    Hello, I have written this piece of code public class Test{ public static void main(String[] args) { List<Integer> list = new ArrayList<Integer>(); for(int i = 1;i<= 4;i++){ new Thread(new TestTask(i, list)).start(); } while(list.size() != 4){ // this while loop required so that all threads complete their work } System.out.println("List "+list); } } class TestTask implements Runnable{ private int sequence; private List<Integer> list; public TestTask(int sequence, List<Integer> list) { this.sequence = sequence; this.list = list; } @Override public void run() { list.add(sequence); } } This code works and prints all the four elements of list on my machine. My question is that will this code always work. I think there might be a issue in this code when two/or more threads add element to this list at the same point. In that case it while loop will never end and code will fail. Can anybody suggest a better way to do this? I am not very good at multithreading and don't know which concurrent collection i can use? Thanks Shekhar

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  • Junit exception test

    - by Prithis
    I have two tests to check the expected exception throw. I am using Junit 4 and has following syntax. @Test(expected=IllegalArgumentException.class) public void testSomething(){ .......... } One of the tests fail even though IllegalArgumentException is thrown and the other passes. Any idea whats missing?? I modified the test which is failing to following and it passes. public void testSomething(){ try{ ............ //line that throws exception fail(); }catch(IllegalArgumentException e) { } }

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  • Occasional weird Glassfish errors, resolved by a restart?

    - by Pooria
    I'm developing a web app using netbeans with GlassFishv3. Every once in a while when I add a new feature in my app, glassfish starts nagging with stupid errors, after a lot of time wasting and panicking, i restart glassfish and run my application again, then suddenly the errors all go away and my site starts acting correctly. (or in case I have made a real mistake, i receive a reasonable & descriptive error from GF.) [Edit: the rest of the question was revealed to have been my own mistake.] But the problems don't end there. Recently, i added the ability to write comments in a (JSF) page, after the user submits their comment, i add it to the database and redirect to the same page, so that hopefully the page refreshes with the new comment, but it wont! The underlying Mysql database shows that the new comment has been added, but the page just wont show the new comment! I've tried everything (e.g. deleting browser cache, using different browsers) but only after restarting GF is when the page shows the new comment! Do you have any idea what the problem could be? Could this be a Glassfish bug? What i am using: JSF2, EJB3.1, JPA, MySql

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  • Restrict number of lines in html JLabel

    - by Mike
    I have a JLabel that needs to display some html-formatted text. However, I want to restrict this to being 4 lines long (and if so, provide a button to see everything). So far, I've tried setting the maximum size manually or via a layout manager. However, both of these solutions can cause part of a line to be displayed.

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  • Drawing translucent bitmaps using Canvas (Android)

    - by mcbitmap
    I have a Bitmap object and want to render it to a Canvas object with varying levels of translucency (i.e. make the whole bitmap partially see through). For example, I have sprites in a game (that are drawn over the top of a bitmap background) that I want to fade out from being opaque to being invisible. Can I do this without having to resort to OpenGL?

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  • Hibernate: same generated value in two properties

    - by Markos Fragkakis
    Hi, I have an entity A with fields: aId (the system id) bId I want the first to be generated: @Id @Column(name = "PRODUCT_ID", unique = true, nullable = false, precision = 12, scale = 0) @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "PROD_GEN") @BusinessKey public Long getAId() { return this.aId; } I want the bId to be initially exactly as the aId. One approach is to insert the entity, then get the aId generated by the DB (2nd query) and then update the entity, setting the bId to be equal to aId (3rd query). Is there a way to get the bId to get the same generated value as aId? Note that afterwards, I want to be able to update bId from my gui. If the solution is JPA, even better.

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  • Refreshing WEB-INF/lib in Google App Engine (with Eclipse)

    - by Adrian Petrescu
    Hi, I've created a new Google App Engine project within Eclipse. I copied several JARs that I need for my application into the WEB-INF/lib directory, and add them to the build path. I make some random calls to these JARs from within the handler, deploy, and everything works fine. However, if I then change one of the JARs outside the project, and copy the new version to WEB-INF/lib (with the same name) and re-deploy, it doesn't seem to be sending the new JAR; everything is still linking to the old one even though it's not even in my WEB-INF/lib anymore. I'm guessing it's being cached by the server or Eclipse is not even realizing something has changed in order to upload the new version. If I just create a new project with the new JAR, everything is fine again (until I have to make another change...) but of course I don't want to have to create a new project for every change to a dependency I make. My question is, how can I make GAE re-upload all the JARs I have from within Eclipse? Thanks in advance, guys :) -Adrian

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